1. Field of the Invention
The invention refers to a method for producing spherical alginate pellets from droplets of an alginate solution delivered from a nozzle, by consolidating the droplets by dropping them into an ion solution, preferably a calcium ion solution, and subsequently washing the alginate pellets removed from the ion solution. The invention further refers to an apparatus for producing spherical alginate pellets from droplets of an alginate solution, comprising a reservoir vessel for the alginate solution; at least one nozzle to which alginate solution can be fed as applicable via a feed line; a collection device, containing an ion solution, for the droplets falling from the nozzle; and at least one device for removing the alginate pellets from the collection device.
Alginate pellets are required, for example, as thickening agents in emulsions, in the cosmetics and food industries, for adhesives and finishes, or as base substances for elastic molding compounds in dentistry, for example. In use, however, the alginate pellets are either completely hardened or only surface-hardened.
Surface-hardened alginate pellets are required, for example, in the cosmetics industry, while completely hardened alginate pellets are required, for example, as supports for enzymes. In order for alginate pellets to be usable to the desired extent, they must be sufficiently pourable and have a narrow particle size spectrum. In particular, a uniform geometry (i.e. a spherical shape) should also be present.
2. Description of the Prior Art FR-A 2 645 439 has disclosed a method for producing spherical alginate pellets intended for the cosmetics industry, according to which an alginate solution is fed to a nozzle from which the alginate solution is delivered in droplet form, subsequently falling into a calcium ion solution. Located in the calcium ion solution is an endless-loop conveyor belt by which the droplets are collected and then transported out of the calcium ion solution.
Since there is no assurance that the droplets are surface-hardened to a sufficient extent as they fall through the calcium ion solution, the alginate pellets removed from the calcium ion solution by the conveyor belt are often flattened. Since the droplets form simply by dripping alginate solution out of the nozzle, a desirable narrow particle size spectrum also cannot be achieved.